Apparatus for the synchronization and relative positioning of two switches



Oct. 1l, 1966 Flled June 5. 1961 Oct. 11, 1966 J. LAVERGNE 3,278,931 APPARATUS FOR THE SYNCHRONIZATION AND RELATIVE y POSITIONING OF TWO SWITCHES Filed June 5, 1961l 6 Sheets-Sheet 2 FIG. 31

Oct. 11, 1966 J. LAVERGNE 3,278,931

APPARATUS FOR THE SYNCHRONIZATION AND RELATIVE POSITIONING OF TWO SWITCHES Filed June 5. 1961 4 6 Sheets-Sheet 5 l', nl 1&0 2

FIG.4

Oct. 11, 1966 J, LAVERGNE 3,278,931

APPARATUS Fon THE SYNCHRONIZATIGN AND RELATIVE POSITIONING OF TWO SWITCHES Filed June 5. 1961 6 Sheets-Sheet 4 Fig.5

ArrazA/gfs Filed June 5. 1961 Oct. 11, 1966 J, LAVERGNE 3,278,931

APPARATUS FOR THE SYNCHRONIZATION AND RELATIVE POSITIONING OF TWO SWITCHES 6 Sheets-Sheet 5 c) A A entre 0 d) (tdk A A /L entre 1 ocr; 11, 1966 NE E SYNCHRONIZATION HJ. LAVERG 3,278,931 AND RELATIVE wITcHEs APPARATUS FOR T POSITIONING OF TWO S 6 Sheets-Sheet 6l Filed June 5, 1961 new! .0a/VCE United States Patent O 3,278,931 APPARATUS FOR THE SYNCHRONIZATION AND RELATIVE POSITIONING F TWO SWITCHES Jean Lavergne, Epinay-sur-Orge, France, assigner t0 Cit- Compagnie Industrielle des Telecommunications, Paris, France, a corporation of France Filed June 5, 1961, Ser. No. 114,834 Claims priority, application France, June 29, 1960, 831,513 13 Claims. (Cl. 340-364) Coding switches have the object of making it possible to code a number of analogue quantities in the course of each of their cycles.

The codingV switch comprises a mechanical switch having a control arm success-ively actuating the contacts of a number of switch housings in the course of a complete revolution made in a period of T seconds. The contacts, N rin number, are each closed for a period T, the change of connection by the arm of the switch from one position to another taking place at regular intervals by means of a -rap-idly operating mechanism controlled by the position of a shaft driven by a motor. Such a mechanism is described in U.S. Patent 3,132,537, dated May 12, 1964. At each ofthe positions are coded a number n of magnitudes, so -that during the rotation of the control arm N n magnitudes are coded, i.e. Nn/ T per second.

The possibility of associating two coding switches for transmitting a double number of items of information through :the same circuits is due to the fact that the time allocated to the passage of the arm to a posi-tion of the switch is not entirely taken Aup in the measurement and the storage of the quantities. A dead ytime must be provided for the period required for the currents to be set up in the ampliers and filters, so that the ltime allotted to the measurement .is substantially less lthan r/2. It is therefore possible to utilize this dead time partially in the measurement and in the storage at a second switch, provided that an appropriate phase relation is established between the arms of the two switches.

Since the various groups of measurements must be transmitted in a particular order, it will be seen that the position of the two a-rms must be such that the second causes the measurement of one group at the switch I to be succeeded by the measurement of a well-defined group at the switch II, and that the measuring time at .the switch II which immediately follows the measuring time at the switch I falls in the interval of lthe dead time succeeding the measuring time at I. It will therefore Vbe seen that a first coarse phase adjustment must be followed by a precise adjustment.

It is the performance of these adjustments that constitutes the object of the present invention.

The device for the relative positioning of two coding switches according `to the invention is characterized by the fact that it comprises two adjusting devices, namely a preliminary or rough adjustment device and a tine or precise adjustment device, 4the preliminary adjustment device determining a relative positioning of the two switches vsuch that the difference from the ideal positioning is less than one switching step, and a ne adjustment device for the positioning ofthe two switches making it possible to alternate the coding times of the two switches with a small residual difference in relation to the regular alternation.

The preliminary adjustment device comprises a device for the adjustment of the angular position by analogue voltage incorporated in each switch and a voltage compa-ring device supplying a pulse at the instant when the vdifference between these voltages changes sign.

The preliminary adjustmen-t comprises in a rst phase the star-ting of the driving motor of the first coding switch 3,278,931 Patented Oct. l1, 1966 and then, when the difference between the stepped voltage locating the variable p'osition of the rst switch and the constant voltage locating the tixed position of the second switch is reversed, the starting of .the driving motor of the second switch.

In the line adjustment device, the position of the shafts driving the arms of .the switches, which shafts carry out a half-revolution in the interval of one step, is located by means of pulses controlling logical ciruits which, if the relative positions of the said pulses reiiects an incorrect positioning, actuate means for slowing down the motor of the switch which is leading the other switch.

Further features of the invention will become apparent from the following description with reference to the iigures of the accompanying drawings, which show by way of non-limiting example a constructional form of the apparatus accord-ing to the invention.

FIGURE l contains the diagrams of the distribution of the measuring times of the two associated coding switches.

FIGURE 2 is a diagram showing the phase relation between the two switches.

FIGURE 3 dia-grammatically illustrates the control shafts of the two switches, with their successive positions.

FIGURE 4 is a diagram of the fine adjustment device.

FIGURE 5 diagrammatically illustrates the two networks of resistances supplying analogue voltages supplying the information regarding the positions o-f the two switches.

FIGURES 6 and 7 are diagrams of .the signals supplied by the elements of the preliminary adjustment device.

FIGURE Y8 diagrammatically illustrates a constructio-nal form of the apparatus according to the invention.

In order to simplify the description and to enable it to be more readily understood, reference will hereinafter be made to a particular choice of T, N, n, f, it being understood that this is only by way of example.

lEach of `the two switches comprises 164 positions (N=164) at which 9 measure-ments (11:9) are made. The time aallocated to each position is equal to 40() milliseconds, so that the period T of the arm of the switch is equal to '164X-0.4=65.6 seconds, during which period 1,476 measurements can be coded.

The change of position of the arm is effected by means of a rapidly opera-ting mechanism controlled by the position of a shaft driven through a gear train (l revolution in 800 milliseconds) 'by a motor rotating at a speed of 1500 r.p.m. (f1 revolution in 40 milliseconds). Twice in each revolution, at intervals of 400 milliseconds, the rapidly opera-ting mechanism causes the shaft of the switch to change position.

The curves of FIGURE 1 illustrate an ideal distribution of the measuring times of two associated coding switches. In FIGURE la, the notches m1, n1, ml and n1 embrace the intervals of 400 milliseconds, each allocated to one posi-tion ofthe arm of the switch I. FIGURElb shows at p1, q1, p.lq1, p"1q"1 the dead times during which Ithe measurements are prevented by transient effects. The diagram of FIGURE 1c shows at x1, y1, x'lyl, x1y1 the times utilized by the measurement and the storage.

The diagrams of FIGURES 1d, le and lf correspond to the preceding diagrams in the case of the switch II. There are marked in FIGURE 1f two measuring periods xgyz, x2y'2 at successive positions, represented in the ideal position in which they are staggered by 200 milliseconds in .relation to those of the switch I.

Referring to FIGURE 1g, the instant t0 and O1 midway in two successive switching intervals of the switch I and -of the 40-millisecond zones centered on to and 0l hoko and hlkl, a satisfactory phase relation will be obtained for the separation of the measurements if the switching instants m2 and n2 are situated within the said zones. However, owing to the necessity for a fixed order of succession in the measurements obtained at the two switches, it is necessary that, if the switching interval m1n1 is allocated to a particular position, for example the position 164, at the switch 1, the interval m2n'2 shouldl be allocated to the corresponding position at the switch II, and a pulse supplied at the instant t2 when the arm of the switch II leaves the position 164 at n2 must therefore be located in the interval l11k1. Under these conditions, 2952 measurements can be coded in 65.6 seconds.

If t'o is the instant 800 milliseconds after to and if a preliminary adjustment has limited to less than i400 milliseconds the maximum possible dierence between the actual position of the arm of the -Second switch and its ideal position, it is ensured that the instant t2 will necessarily be located in the interval tol. Let A (FIGURE 2) be the 380-millisecond zone th1, C the 380`millisecond zone k1t0, and B the central l0millisecond interval h1k1. The phase relation will be correct and the switches will be synchronised as long as t2 is located in zone B. If t2 is in the zone A, it will be said that the switch I is leading the switch II, and if it is in the zone C, it will be said that it is lagging.

According to the invention, the instants t0, t'0 and the zones B associated with the instant 01, commencing at the the time t1=020 ms., which elements make possible a defining the phase relation between the two switches, are located by the following means.

It has been stated in the foreging that the shafts determining the step-by-step rotation of the arm of each of the switches carry out one rotation in 800 milliseconds and start by means of a cam-operated mechanism the progress of the arm of the switch into two opposite positions at the instant of the entry into the zones centered on J1 and J'1 or J2 and 12 of a reference diameter of the said shafts (FIGURE 3).

For the shaft `associated with the switch I (FIGURE 31), the position J1 corresponds successively to m1, m1 the position J'1 to n1, n1, and so on.

The instants to, t'o are defined by the entry of the reference diameter into the position To offset in relation to I1 by 1r/2 in the direction of rotation indicated by the arrow (instant later by 200 milliseconds than that of m1), the instants t1, t1=t1{800 ms. being defined by the entry of the same diameter into the position T1 offset in relation to T0 by 1r 380/400, i.e. 19T/20.

Pulses are supplied at the instants to, to, t1 by means of which an example will hereinafter be given, and the Zone B is characterised by the change of state of a monostable trigger circuit 'when it receives the pulse at its input at the time t1, and its return to its pri-or state 40 milliseconds later.

For the second switch (FIGURE 32), in which the passage of a reference diameter through J2 and 12 corresponds to the switching instants m2, m2 of FIGURE ld, the instant t2 will be defined by the passage of the reference diameter through the position LV2.

In order to retain or to restore the correct phase relation between the two switches, the invention provides members by means of which, in accordance with the position of the pulse t2 of the second switch in relation to the intervals A, B, C, defined by the first, it is possible to determine the reduction of the speed of the motor controlling the progress of one or other of the two switches, of the switch II in the zone A and of the switch I in the zone C, or to exert no action in the zone B.

These speed reducing actions are controlled by the state of binary flip-flops BBZ1, BBZ2 (FIGURE 4) associated respectively with the members adjusting the speed of the two motors, and of which the inputs receive, at the time of the pulse supplied at the time l2, signals `depending upon the position of the said pulse. The posting of the signal 1 at one of the outputs, for example the zero output,

determines the speed reduction of the first or second motor respectively.

The logical circuits by means of Iwhich this result can be obtained are illustrated in FIGURE 4. They comprise two logical OR circuits and four logical AND circuits comprising diodes of known type. A11, A1, A2 represent amplifiers receiving at their inputs the pulses supplied at the times to, t1, t2 respectively. BB1 is a bistable flip-flop whose inputs are connected to the outputs of A0, A1. The binary signals set up at the outputs of the said flip-flop will be denoted by a and respectively.

Depending upon the zones, they take the following values:

Zone A: a=l, 6:0 Zones B and C: a=0, '6:1

BM1 is a flip-flop to the input of which the signal 2 is applied. The negative pulse registered by the signal at the instant t1 changes the normal state of the flip-flop for a period equal to 40 milliseconds, that of the interval B. In the zone B, b being the output signal of BM1, we have b=l, While in the other z-ones we have 11:0.

The output of the amplifier A2 is connected to the input of a monostable flip-flop BMZ whose output signal C represents the value l only at the instant t2 of the pulse.

The logical OR circuit and the inverting circuit In supply the output signals representing (a-j-b) and (m) respectively, while the circuits ET1, ET2, ET3, ET4 supply the output signals ac, ca, c(a}b), dm) respectively. The bistable Hip-flop BBZ1 receives :at its input 0 the signal c(ajb) and at its input 1 the signal dm). The bistable ip-op BBZ2 receives at its input 0 the signal c and at its input 1 the signal ac.

It will thus be seen that there are received at the two terminals of each of the binary flip-flops at the instants of the pulses (t2) signals which always represent opposite binary digits, of which only one is consequently effective.

In the zone B, c and c(a}b) represent l. The effect of the signal 1 at the zero input terminals is to apply the zero signal to the output terminals 0 of the two flip-flops. Therefore, no retarding action is exerted on the motors, and this is appropriate for maintaining a correct position.

In the zone A, ca=l, which gives a signal 1 at the output 0 of BBZ1), Iand the speed reduction of the second motor is thus obtained. On the other hand, since c(a|b) remains equal to 1, no action is exerted on the rst motor.

In the zone C, '-I- b represents the binary digit l, which is set up at the output 0 of BBZ1, which results in a reduction of the speed of the first motor, while since c is equal to 1, no acti-on is exerted on the second motor.

The desired effects can thus in fact be obtained 'by means of the described logical circuits. There will now be described the principle of the operating device for effecting the preliminary (so-called rough) adjustment at the starting of the motors, which is rendered inoperative 'when a sufficiently small phase difference has been set up, and the fine adjustment device is then substituted therefor.

The principle applied is as follows: At the starting of the motors, the motor associated with the switch I is fed with full power, while the second motor is not fed. The 164 positions of the switch are characterised by voltages varying linearly from the position 1 to the position 164. The arm of the switch II is then stationary and indicates a fixed constant voltage corresponding to its position. The arm of the switch I indicates a stepped voltage. At the instant when these voltages are equal, the switch II i-s set in operation by a comparing device.

The precise adjustment device is placed in circuit only about l second after the starting of the second motor so as to enable the latter to reach its full speed.

There will now be given a number of examples of the manner in which the precise adjustment and the preliminary adjustment are carried out.

For the precise adjustment, the pulses employed for bringing the arms of the switches into phase are obtained by the travel of a magnetic arm, conforming to the position of the cam-operated mechanism past magnetic heads disposed in the positions marked T and T1 in FIGURE 31 in the case of the first switch, and in the position marked J2 in FIGURE 32 in the case of the second switch.

With regard to the means for reducing the speed of the motors, they depend upon the type of motors employed.

In a preferred construction, the motors are of the synchronized asynchronous type. Having ample dimensions, these motors remain in step once the synchronization has been effected. In order to obtain the synchronization, the slip of the motor which is to be slowed down is effected by reducing its feed current by the insertion of a set of resistances in series in each phase, which produces the out-of-step condition.

The outputs of the flip-flops BBZ1, BBZ2 are connected to the windings of two relays which control switches which effect the series connection of resistances in the feed wires of the motors associated with the switches 1 and 2 respectively.

The preliminary adjustment circuit will now be described with reference to FIGURE 5 et seq.:

FIGURE 5 shows the two networks of 163 identical resistances R -supplying analogue voltages giving the information regarding the positions of the two switches. These two networks are fed by a common source (of 24 volts in the example given) and the same current flows therethrough.

Resistances r1 and r2 are connected to the two networks on the side of the 24-volt terminal, bringing to about 8 volts the voltage difference across the terminals of the networks, while a resistance R/2 is disposed between the terminal 0 and the input of the second network.

The voltage difference between two successive positions is %63 volts at the two networks, but owing to the additional resistance R/ 2 the corresponding voltage levels in the two switches are staggered by a half-step (upwards at the second).

FIGURE 6 shows at 6a the stepped signals obtained in the case of switches having only four positions in the case of the ideal staggering of the arms.

These signals are applied to the input of av differential amplifier AD (FIGURE 8), the voltage curve at the output of which is that illustrated in FIGURE 6b, which comprises ZOO-millisecond crenulations at regular intervals except at the instant of the return to zero of the analogue voltages which corresponds to a void.

There are shown at 6c the positive pulses which are set up at the flip-flop input connected to the output of the differential amplifier AD, which flip-flop is sensitive only to positive pulses. These pulses are spaced apart by 40() milliseconds, except at the return of the analogue voltages through Zero, where a spacing of 800 milliseconds is observed.

This result is not confined to the example of FIGURE 6, and is obtainable regardless of the number of positions of the switch.

There will be seen in FIGURE 7 at 7a and 7b the modification resulting in the case of these curves from a backward shift of 800 milliseconds of the second switch in relation to its ideal position.

There will be seen at 7c the corresponding positive pulses, whose repetition time is equal to the period of the switches, which is a general result.

FIGURE 8 illustrates the whole apparatus according to the invention in its preferred form.

MC1, MC2 represent the two switching motor sets. The first motor is fed by the poles 1, 2, 3 from a threephase voltage source at its terminals 11, 12, 13. The second motor is fed at 31, 32, 33 at the downstream terminals of a general contactor S1.

The terminals of the assembly MC1 at which there are set up at the times to and t1 the pulses utilised in the pre- 6 cise adjustment are designated 4 and 5, 6 is the terminal of MC2 at which the pulse is supplied at the time t2, and 7 and 8 are the terminals of MC1 and MC2 at which the analogue voltages giving the position information are set up.

The fine adjustment device illustrated in FIGURE 4 is designated 9, of which the outputs 10 and 20 are the output terminals 0 of the ip-fiops BBZ1, BBZ2, which are connected to the negative pole of the feed battery through the windings of relays 14 and 24 which, when their contacts are in the operating position, place the windings of speed reducing contactors 15 and 25 respectively on open circuit between 32 and 33, thus bringing about the insertion of speed reducing resistances 16 and 26 connected to the contact terminals of the contactors 15 and 25 respectively.

The closing of the contactor S1 by the starting button M, which contactor remains self-energized, ensures feeding of the first motor and, owing to earthing of the zero input of the flip-flop BB2 at 27, brings about the establishment at the output 1 of BB2 of a Zero voltage, the energization of the relay 3f) connected between the said output and the negative pole of the feed source and consequently the breaking by means of a contactor S2 of the feed circuits of the second motor, which remains inoperative.

At the same time, earth applied to a terminal 34 of the precise adjustment device brings the flip-flops BBZl, BBZ2 of the fine adjustment device (FIGURE 4) into the position in which the relay 14 and 24 are inoperative, which results in short-circuiting of the speed reducing resistances 16 and 26.

The terminals 7 and 8 of the motor-switches MC1 and MC2 are connected respectively to the input terminals 7 and 8 of a differential amplifier AD. When the analogue voltages at the input terminals 4of the differential amplifier AD become equal, the crenulated curve 6b represents a discontinuity, and a pulse is set up at the output 29 of the differential amplifier AD, which pulse, applied to the input 1 of the flip-fiop BB2, changes its state if it is positive (FIGURE 6) and produces the return of the contact of the relay 30 to the inoperative position. The control circuit of the contactor S2 is then closed and remains self-energized, and the second switch motor MC2 is started. At the same time, earth is disconnected fro'm 34, whereby the fine adjustment circuit 9 is released. The operation of this circuit may delay the bringing of the motors to their normal speed, and a resistance-capacitance delay device is therefore provided, which has a time constant of about 1 second.

The correct synchronization of the switch motors MC1, MC2 is indicated by the extinction of a red pilot light R and the ignition of a green pilot light V. For this purpose, a bistable ffip-fiop BB3 receives at its input terminal 1 the pulses (t2) about every 800 milliseconds, while its input terminal 0 is connected to the output 29 of the differential amplifier AD. The output 0 of the flip-flop BB3 is connected to the negative feed pole through a delay device 35 and a relay winding 36 whose contact feeds in its inoperative position a green pilot light V and in its operative position a red pilot light R.

A positive pulse (t2) applied to the input 1 of the flipflop BB3 has the effect of causing a voltage in the neighbourhood of zero to be set up at the output 0 of BB3, which results in feeding of the winding 36 and causes ig nition of the red pilot light R, while a positive pulse applied to the input 0, coming from 29, changes the state of the flip-flop BB3, and causes a negative voltage to be set up at the output 0 of BB3 and consequently the release of the relay 36 and the ignition of the green pilot light V.

Now, it has been seen that the pulse (t2) occurs at the instant when the rapidly operating mechanism of the second switch commences to operate. Therefore, t2 precedes the change of position of the second switch by a period which may vary from 5 to 25 milliseconds depending upon the accuracy of the mechanism. In the case of correct synchronism of the switch motors MC1 and MC2 (FIG- URE 6), the pulse (t2) is therefore always succeeded by a pulse emanating from the output of the amplier AD at a time interval not exceeding 25 milliseconds (FIG- URE 6d) The delay device 35 prevents the response of the relay 36 during this interval, so that the green pilot light remains continuously alight.

In the event of incorrect synchronism, on the other hand, the positive pulses at the input of BB3 are set up only once per period of the switches, which period is equal to 65.6 seconds in the case of 164 positions, and it will be seen (FIGURE 7d) that the state of the flip-dop will generally be fixed by the pulses (t2), the positive pulses at the output AD being capable of producing the ignition of the green pilot light only for a period obviously shorter than 800 milliseconds.

When an incorrect synchronism is observed, the general stop button A is operated and the operations are recommenced. This, however, is exceptional and can occur only as a result of disturbing currentsat the input of the amplifier AD.

On the other hand, the contacts 37 and 38 supplied by the speed reducing contactors and 25 during the precise adjustment determine the ignition of an orange pilot light OR, which thus indicates the adjustment periods.

What is claimed is:

1. Apparatus for the synchronization and relative positioning of two coding switch means, comprising:

two separately controllable switch driving means effectively providing a plurality of switching steps with the coding times thereof alternating,

two adjusting means including a preliminary adjusting means operatively connected to said switch means and driving means, and Ia fine-adjusting means for controlling the fine adjustment of the positioning of the two switch means to enable the coding times of the two switch means to alternate with a slight residual diierence in relation to the regular alternation thereof,

said preliminary adjusting means for determining a relative positioning of the two switch means such that the difference from the ideal positioning thereof is smaller than one switching step,

said preliminary adjusting means further including switch position-locating means operable by analogue voltage and voltage comparing means operatively connected with said driving means.

2. Apparatus according to claim 1, wherein said preliminary adjusting means includes locating means operable by an analogue voltage incorporated in each switch means for locating the angular position thereof and voltage-comparing means operable to supply a pulse at the instant of change in sign in the diierence between these voltages, each switch driving means including an electric driving motor, said preliminary adjusting means further including rst means operable in a first phase for starting the driving motor of one of the coding switch means, and second means operable in a second phase for starting the driving motor of the other coding switch means upon reversal of the difference between the stepped voltage loeating the variable position of said one switch means and the constant voltage locating the -other switch means.

3. Apparatus according to claim 2, further comprising speed-reducing means including a speed-reducing contactor for each driving motor, control windings for the speedreducing contactors, and relay means controlled by said line-adjusting means and operatively connected with said control windings.

4. Apparatus according to claim 2, wherein said volt- .age comparing means includes a differential amplifier to the input of which are applied the analogue voltages, flipllop means operatively connecte-d to the output of said differential ampliiier, and relay means controlled by said flip-flop means and operable to control the contactor of the motor for the other coding switch means.

5. Apparatus according to claim 2, wherein speed-reducin-g means are operatively associated with the driving motor of each switch means and each switch means has a driving shaft for driving a respective switch arm, said shafts carrying out a half-revolution in the interval of one step, and locating means in said tine-adjusting means for locating the position of said shafts including pulseproducing means for producing pulses of which the relative position reflects the position of the switch means and logical circuit means operatively connected with said pulseproducing means and operable to actuate, in response to a relative position of said pulsesy reilecting an incorrect positioning, the speed-reducing means of the motor driving the then leading switch means.

6. Apparatus accordin-g to claim 5, wherein said logical circuit means include binary flip-flop means having inputs and outputs, said outputs being operatively connected with said speed-reducing means, and means operatively connecting said pulse-producing means with said inputs to apply to said inputs at the instant of the reference position pulse supplied by the other switch means, signals depending upon the position of the said last-mentioned pulse.

7. Apparatus according to claim 6, further comprising a synchronism indicator including indicating pilot lamp means, a relay for controlling said lamp means, a bi-stable flip-flop device which receives the reference pulses of the other coding switch means and is operatively connected to the output of said differential amplifier, and a delay device operatively connecting said bi-stable flip-flop device with said relay.

8. Apparatus according to claim 1, wherein speed-reducing means are operatively associated with each driving means including a motor and .each switch means has a driving shaft for driving ya respective switch arm said shafts carrying out a half-revolution in the interval of one step, and locating means in said tine-adjusting means for locating the position of said shafts including pulseproducing means for producing pulses of which the relative position rellects the position of the switch means and logical circuit means operatively connected with said pulseproducing means and operable to actuate, in response to a relative position of said pulses reecting an incorrect positioning, the speed-reducing means of the motor drivin-g the then leading switch means.

9. Apparatus according to clai-m 8, wherein said logical circuit means include binary flip-op means having inputs and outputs, said outputs being operatively connected with said speed-reducing means, and means operatively connecting said pulse-producing means with said inputs operable to `apply to said inputs, at the instant of the reference position pulse of the other switch means `supplied by said pulse-producing means, signals depending upon the position in time of each reference position pulse.

10. Apparatus according to claim 9, wherein said speedreducing means includes a speed-reducing contactor for each driving motor, control windings for the speed-reducing contactors, and relay means controlled by said neadjusting means and operatively connected with said control windings.

11. Apparatus according to claim 1, comprising means for producing reference position pulses for each of said switch means, and wherein said Ifine adjusting means includes a bi-stable flip-flop means having input and output means, the reference position pulses of one switch means being applied to the input means of said bi-stable flip-Hop means, a monostable flip-flop means having input and output means, the reference position pulses of the other switch meansbeing applied to the input means of said monostable flip-flop means, logical circuit means with the inputs thereof connected to said output means for combining in the outputs thereof the signals supplied thereto, and two bi-st-able flip-flop means receiving in the inputs thereof the combination of signals from said logical circuit means and each supplying a current for the control of the contactors for the reduction of the speed of the driving motors for said `coding switch means.

12. Apparatus according tol claim 4, further comprising a synchronism indicator including indicating pilot lamp means, va relay for controlling said lamp means, .a Ibi-stable Hip-flop device which receives the reference pulses of the other coding switch means and is operatively connected to the output of said differential amplifier, and a delay device operatively connecting said bi-stable ip-op device with said relay.

13. Apparatus for the synchronization and relative positioning of two coding switches, comprising two coding switch means effectively providing a plurality of switching steps with the coding times thereof alternating, .two adjusting means operatively connected with said two coding switch means including preliminary adjusting means for determining a relative position of the two switch means such that the difference from the ideal positioning thereof is smaller 4than one switching step, and line-adjusting References Cited by the Examiner UNITED STATES PATENTS 2,534,842 12/1950 Wallace 340-182 X 2,929,941 3/1960 Bobo 307-87 3,005,151 10/1961 Ale 307-87 3,012,229 12/1961 Berman etal 340-187 X NEIL C. READ, Primary Examiner.

MILTON O. HIRSHFIELD, Examiner.

G. G. JENSEN, A. H. WARING, Assistant Examiners. 

1. APPARATUS FOR THE SYNCHRONIZATION AND RELATIVE POSITIONING OF TWO CODING SWITCH MEANS, COMPRISING: TWO SEPARATELY CONTROLLABLE SWITCH DRIVING MEANS EFFECTIVELY PROVIDING A PLURALITY OF SWITCHING STEPS WITH THE CODING TIMES THEREOF ALTERNATING, TWO ADJUSTING MEANS INCLUDING A PRELIMINARY ADJUSTING MEANS OPERATIVELY CONNECTED TO SAID SWITCH MEANS AND DRIVING MEANS, AND A FINE-ADJUSTING MEANS FOR CONTROLLING THE FINE ADJUSTMENT OF THE POSITIONING OF THE TWO SWITCH MEANS TO ENABLE THE CODING TIMES OF THE TWO SWITCH MEANS TO ALTERNATE WITH A SLIGHT RESIDUAL DIFFERENCE IN RELATION TO THE REGULAR ALTERNATION THEREOF, SAID PRELIMINARY ADJUSTING MEANS FOR DETERMINING A RELATIVE POSITIONING OF THE TWO SWITCH MEANS SUCH THAT THE DIFFERENCE FROM THE IDEAL POSITIONING THEREOF IS SMALLER THAN ONE SWITCHING STEP, SAID PRELIMINARY ADJUSTING MEANS FURTHER INCLUDING SWITCH POSITION-LOCATING MEANS OPERABLE BY ANALOGUE VOLTAGE AND VOLTAGE COMPARING MEANS OPERATIVELY CONNECTED WITH SAID DRIVING MEANS. 